High molecular weight poly (epsiloncaprolactone) (also known as "polycaprolactone") has been used as a thermoplastic molding compound for general-purpose modelmaking and dentistry. References describing polycaprolactone molding compositions include U.S. Pat. No. 4,835,203, Kokat (Japanese Published Pat. Appl.) Nos. 63-171554 and 63-270759, and TONE.RTM. POLYMERS P-300 AND P-700 High Molecular Weight Caprolactone Polymers (1988 product literature of Union Carbide Corp.). The polycaprolactone described in Kokai No. 63-171554 is said to be polymerized in the presence of a small amount of epoxy resin, which is said to improve the hydrolysis resistance of the polycaprolactone.
Deldent Dental Supplies Co., Ltd. sells a heat-softenable custom tray material referred to as the "formable base impression" or "FBI" denture tray system. The FBI tray is immersed in hot water to soften the tray, placed in a patient's mouth while warm and shaped to conform to the patient's arch. The FBI tray is said to return to its original configuration if immersed again in hot water.
U.S. Pat. Nos. 4,240,415 and 4,483,333 describe radiation-crosslinked polycaprolactone orthopedic casts. The patents refer to the possible inclusion of "chemicals containing two or more double bonds in each molecule". The casts are radiation-crosslinked using several 5 megarad exposures in an electron beam apparatus.